In December 1831 a youthful Charles Darwin, recently graduated from Cambridge University, set sail as the ship's naturalist on the HMS Beagle, his heart filled with the promise of the adventure that lay before him. What did Darwin know? He could not have anticipated that the conclusions he would draw from his field notes about life on the Galapagos Islands would transform our understanding of the nature of animals and their relationship to that special animal of a human kind. He was the grandson of the controversial physician Erasmus Darwin, living in the heyday of the British Empire at the very moment in which the dual passions for science and exploration converged. He was a Victorian gentleman in pursuit of knowledge and adventure, a disinterested spirit in the midst of the global struggle among nations for profit and power. He was also a great reader of the many important works of science and travelers' tales of the preceding generations. He was not yet a "scientist"—a term that would not enter the lexicon until the early 1830s with the formation of the British Association for the Advancement of Science. Much as we would like to proclaim Darwin the intellectual beacon of the nineteenth century, he was equally shaped by late eighteenth-century Romantic habits of mind, scientific practices and experiments in writing about the natural world. The mature Darwin was by no means a Romantic in any aesthetic sense. The Malthusian-inspired concept of evolution that he would eventually articulate in On the Origin of Species did not attempt to establish nature's poetic unity, which characterized the Romantic movement at its height. Yet the eagerness of 22-year-old Darwin to follow in the footsteps of recent scientific explorers made him the final and most brilliant product of Romantic science.

To Richard Holmes, Darwin's 1831 expedition was the apogee of an "age of wonder" inaugurated by the wealthy gentleman-naturalist Joseph Banks in 1768 when he set sail with Captain James Cook on the Endeavour for the island of Tahiti to observe the transit of Venus. With a lively wit and a meticulous attention to detail, Holmes charts in The Age of Wonder the era in which Romanticism's long rebellion against the image of a clockwork universe inspired great works of knowledge and creativity—what he terms "the second scientific revolution." The objective developments in science of the preceding century gave way to subjective reflection about the meaning of understanding nature. Poets such as Wordsworth, Coleridge and Keats marveled at the new vision of the world wrought by science. At the same time, the British astronomers, naturalists, chemists and experimenters of their generation developed a conception of the world that was, in its own way, profoundly poetic. In private contemplation, public lectures and books written for a general audience craving the latest and most exciting discoveries, they opened up vistas of the imagination, exciting all who knew them about the potential for science to be a spiritual compass as well as a productive engine for the advancement of their society. Put another way, we might think of The Age of Wonder as a story of how the spirit of Newton gradually gave birth to Mary Shelley's Frankenstein, or The Modern Prometheus (1818) and subsequently reinvented itself in the generation that Darwin embodied.

But let us return to Tahiti and lose our clothes for a while, as Joseph Banks did for about three months after he disembarked from the Endeavour in the spring of 1769. When Banks returned to England two years later, his mouth was full of Tahitian words; his bags were laden with trinkets, his specimen boxes rich with seeds and plants and his notebooks all but bursting at the spine with the observations of an anthropologist in the making who had fully immersed himself in a truly different culture. Banks would be celebrated by the British people for surviving this arduous and exotic Pacific voyage. With his ascent to the presidency of the Royal Society of London in 1778 and the knighthood bestowed upon him as director of Kew Gardens in 1781, he became the leading figure of the British scientific establishment and its principal patron until his death in 1820. Under his watchful guidance, British science grew and matured.

Yet the most salient aspect of Banks's voyage was his personal response to the unsettling isolation and biodiversity of Tahiti. In a way that others found alternately fascinating and disturbing, Banks had temporarily become a different man. Freed from the trappings of his own society, he had allowed himself to be seduced by Tahitian customs, the seeming ease of social relations and the rhythm of rituals. Banks observed and participated, and did not conceal its effect on his psyche even if he could never bring himself to publish a full account of all that he had seen and experienced on the voyage of the Endeavour. Had he remained permanently at a remove from civilization, his life would have become a tale of a real-life Robinson Crusoe, yet another Englishman lost on a remote island. Instead Banks transformed his encounter with Tahiti into the basis for an incredible career as Britain's unofficial statesman of science, creating a web of scientific correspondents all over the world. A breakfast invitation to his home at 32 Soho Square was the first steppingstone for any ambitious scientist aspiring to a good career in the next fifty years. But the memory of his song of Tahitian innocence would continue to inspire epic poetry well into the nineteenth century.

If Banks embodied the spirit of those wealthy British gentlemen who saw science as a global adventure of self-discovery—an attitude that eventually gave birth to the Royal Geographical Society in 1830 and the great age of polar expeditions and mountaineering, which made men such as Robert Scott into the heroes of a later era—the modest and self-effacing William Herschel represented the other face of science in the late eighteenth century. The son of a Hanoverian regimental musician, young William first set eyes on the cliffs of Dover when he accompanied his father—and the band—to England in 1756. His musical abilities eventually earned him the position of organist at the Bath Octagon Chapel. While playing for the well-heeled inhabitants of a fashionable resort town, Herschel nurtured his passion for astronomy. In 1766, several years before Banks sailed for Tahiti, Herschel purchased a secondhand refracting telescope and began his journal of celestial observations. A tinkerer and a thinker, he soon realized the limits of this kind of instrument. He began to develop his own version of the reflecting telescope first presented to the Royal Society of London by Isaac Newton in 1672 but rarely used by astronomers before the late eighteenth century. He made his own metal mirrors, experimenting with different diameters as well as the length of the telescope to achieve the best effect—an upright image of the heavens on a polished surface with a wide angle of vision.

Herschel's succession of increasingly powerful telescopes yielded some of the most breathtaking observations of the age. With the devoted assistance of his sister Caroline, who emigrated from Hanover in 1772 and became an accomplished astronomer in her own right, Herschel identified the Pole Star as a double star. Within a decade he increased the number of known nebulae tenfold, and then doubled that number. His uncanny powers of observation and dedication to his science produced legions of admirers. If Herschel had simply been a collector of data, he might not have earned a principal place of honor in Holmes's account of Romantic science. It was his vision of the universe that made him a source of poetic inspiration. Thanks to Herschel's keen eye, the universe was no longer a series of points of light etched into the inverted bowl of the heavens; it was a product of deep space and ultimately deep time. The late-eighteenth-century heavens appeared immense but measurable, filled with all sorts of new and surprising phenomena (though lacking the forms of extraterrestrial life that Herschel ultimately had hoped to discover).

Herschel recognized that the varying brightness of stars was a product of distance rather than size. Sweeping the heavens every night, he meticulously rearranged the universe, locating each celestial object with a new degree of precision on a new map of the skies. Examining the constellation of Gemini on March 13, 1781, he observed an unusual object. He initially identified it as a comet. Three weeks later, he changed his mind. During the spring and summer of 1781 virtually every major astronomer confirmed the exhilarating discovery of Uranus, the first new planet to be identified since antiquity. The German organist made the pilgrimage to London to meet Banks, who instructed the Royal Society to admit Herschel to its ranks and to crown his accomplishment by awarding him the Copley Gold Medal. By producing a telescope that was more accurate than the Royal Greenwich Observatory's celebrated and costly instruments, Herschel rightfully earned his place as one of the true wonders of his age.

Herschel's ambitions for the understanding of the cosmos continued to grow with the size of his telescope. In Holmes's account, we see how a German reader of Kant disclosed the existence of an unbounded and infinite universe that nurtured the dreams of the British Romantics. Coleridge would recall marveling with his father, as a boy of 8, at the wonder of the winter sky in 1781. Keats fondly remembered schoolboy games inspired by the new constitution of the heavens. They belonged to a generation whose parents and tutors conveyed the excitement of Herschel's telescope, which quickly became a commercial product. They learned to read the skies like a vast musical composition of the kind that Herschel may have inspired in the mind of Joseph Haydn, who visited the astronomer in his observatory in 1792. Was the doughty Herschel the inspiration for Coleridge's Ancient Mariner? Holmes would have us believe that his was one of several steady hands directing the rudder of the British imagination until his death in 1822.

But the Romantics were not only inspired by bright and tangible accomplishments enlarging the stock of scientific knowledge. They were just as transfixed by the failures of science and the sense of disequilibrium or estrangement that shadowed scientific undertakings. Holmes treats the balloon craze inaugurated by the Montgolfier brothers in 1783 as a crucial episode of Romantic deflation. A fascinating marriage of the new chemistry of air and the ancient dream of aviation, balloon trials initially promised myriad new and transformative experiences. The ascent of the first aeronauts tested the limits of human endurance—and by the time a balloon reached the altitude of 23,000 feet it confirmed everything chemists and physiologists said about the necessity of air to life. But before an enlightened aeronaut passed out in the thinning atmosphere of Herschel's infinite space, there were meteorological observations to make. Herschel fantasized about seeing space from space with an airborne telescope. Shelley remarked that clouds no longer seemed the same after they had been punctured by a balloon filled with barometric instruments. Yet the perils of ballooning—a dangerous and costly sport for few with a high mortality rate among its most enthusiastic participants and an even higher degree of equipment failure—revealed its limitations, making it a passing curiosity. Far better to travel through space seated inside one of Herschel's famously large telescopes—the true spaceships of his time.

The limits of geographic exploration were no better represented than by the glorious adventures of physician Mungo Park. His Travels in the Interior of Africa (1799), an account of an expedition funded by the nascent Africa Association, the precursor to the Royal Geographical Society, made him the most celebrated British explorer at the turn of the century. Unlike Banks, Park did not rest on his laurels after a single voyage. He returned to the Gold Coast of West Africa in 1805, still in search of Timbuctoo. There he disappeared—or perhaps, improbably, he survived but did not return. His legendary heroism would haunt the poetry of Wordsworth, Keats, Shelley and Tennyson. His fellow Scotsman Sir Walter Scott would proudly recall that Park had once been his physician. Park's willingness to sacrifice himself for the advancement of knowledge made him the scientific paragon of every British geographer, anthropologist and explorer who followed in his footsteps.

In 1801, four years before Park disappeared in a boat on the Niger, a young Cornwall chemist knocked on the door of Banks's Soho Square townhouse. Inspired by the revolutionary work of chemists such as Joseph Priestley and Antoine Lavoisier, the handsome and charismatic Humphrey Davy would become the most successful British chemist of his generation. A flamboyant lecturer and experimenter, and an inveterate social climber, Davy made the latest discoveries in chemistry thrilling and seductive to a public eager to experience the heady sensations of knowledge. Priestley had inadvertently invented fizzy water while observing the effect of brewing on beer. While employed by the Bristol Pneumatic Institute, Davy instead would find a terrestrial application for balloon technology. Collaborating with James Watts's son Gregory, he found the perfect apparatus through which to inhale nitrous oxide. In spring 1799 Davy invited a circle of friends to experience the giddy effects of laughing gas. He was inspired enough to write a poem about it. Davy's celebrated self-experiment, in which he inhaled six quarts of N2O on May 5, 1799, led to a loss of consciousness, feeling and memory. In 1844 the surgical potential of nitrous oxide would be demonstrated during dental surgery by Dr. Horace Wells in Hartford, Connecticut—far too late for Fanny Burney to benefit from its effects during the mastectomy she underwent in Paris at the hands of one of Napoleon's surgeons on September 30, 1811, leading her to pen one of the most eloquent and vivid accounts of pain ever written. In the short term, the psychosomatic effects (to borrow Coleridge's term) of Davy's discovery fascinated his contemporaries. He had invented a new pleasure for which they had no name.

If Romanticism began as an exploration of the enhancement of the senses, at the height of its success it grappled with the novel sensation of feeling nothing at all. Coleridge claimed that listening to Davy shortly after his discovery of laughing gas had enlarged his capacity for metaphor. The image of Davy as the nineteenth century's Timothy Leary, however, is softened by his subsequent career as a scion of the British scientific establishment: he was feted by Banks and admitted to the Royal Society, and he married well and educated the British gentry with his spellbinding lectures and demonstrations at the Royal Institution on Albemarle Street. It was after a teenage Mary Godwin observed Davy's performance at an Institution lecture in 1812—a time when Davy was celebrated for his isolation of potassium and for pioneering its role in electrochemical analysis—that she began to think about the good and ill of science. She would recall this experience during a discussion of the anatomist Giovanni Aldini's shocking reanimation experiments, which inspired her writing of Frankenstein. Her husband, Percy Bysshe Shelley, also found Davy a source of inspiration, and they seem to have read and discussed his chemistry together.

More than any other protagonist of Holmes's narrative, Davy was the poet's scientist. He summered in the Lake District, scrambling up its peaks and crossing its verdant meadows with the likes of Wordsworth, Scott and Robert Southey while debating the promise and futility of science. Such conversations, both in England and during his continental Grand Tour, would provoke his own melancholic reflection on the meaning of a life in science, his posthumous Consolations in Travel, or the Last Days of a Philosopher (1830). Davy also wrote enough poetry to fill another posthumous book. He rhapsodized about fly-fishing. He continued to make significant chemical discoveries—isolating chlorine, iodine and methane. Appropriately he would die from a lifetime of toxic pursuits on the shores of Lake Geneva in 1829, not far from the villa in which Byron and the Shelleys challenged each other to write an account of modern science in the summer of 1816. It is tempting to think that they talked of these matters when Davy visited Byron in Venice during his own travels.

Davy's reputation as a scientist rested not only on his ability to make the science of chemistry accessible and pleasurable—transforming it into a kind of poetry that would indeed be celebrated by all the leading British poets—but also on his tangible success as an early practitioner of industrial chemistry. His invention of the Davy Lamp in 1815 at the request of the Coal Mines Safety Committee was a triumph for science's utility at the dawn of the Industrial Revolution. He was also smart enough to recognize the potential of a young bookbinder and blacksmith's son, Michael Faraday, while begrudging him any recognition for his independent accomplishments. Faraday's work on electromagnetism, his investigations of chlorine and benzene, his research on coal dust and metal corrosion and popular lectures on subjects such as the "Chemical History of a Candle" made him a distinguished and far more humble successor to his worldly employer, Davy. But Faraday would never be the poet's scientist.

In the 1820s Banks, Herschel and Davy died, as did many of the greatest poets who celebrated them. Holmes closes his epic account of the age of Romantic science by reflecting on their legacy. The task of advancing scientific knowledge fell to men such as the geologist Charles Lyell, mathematician and inventor Charles Babbage, philosopher William Whewell and Herschel's son, John, a mathematician, astronomer and pioneer of photography whose A Preliminary Discourse on the Study of Natural Philosophy (1831) would captivate a young Charles Darwin, his head already full of the works of science and exploration of the previous century. Awash in honors that belonged more to his father, John Herschel escaped the scientific hothouse of London to find room to think, observe and experiment, unconstrained by the pressures of society on the talented only son of a famous scientist. Darwin admired Herschel, a man of independent means beholden to no patron or institution. In 1836, during his Beagle voyage, Darwin visited him in Cape Town, South Africa, where Herschel was conducting astronomical observations and making botanical illustrations. Darwin's conversations with Herschel in Cape Town seem to have further stimulated his interest in Lyell's work. For these and other accomplishments, the younger Herschel became the toast of British scientific society upon his return, in 1838. He would be buried in Westminster Abbey in 1871—an honor accorded to Newton and refused by Faraday. A decade later, Darwin joined him there.